Recent developments in 3GPP standardization relate to Long Term Evolution (LTE) and Long Term Evolution Advanced (LTE Advanced) telecommunications networks and devices. LTE and LTE Advanced, also known as the 4G (i.e. fourth generation) mobile communications standard, is a standard for wireless communication of high-speed data for mobile phones and data terminals. It is a successor of GSM/EDGE (also known as 2G or 2.5G) and UMTS/HSPA (also known as 3G) network technologies, increasing the capacity and speed using a different radio interface together with evolutions and improvements in the radio access network and the core network.
Single-Cell Point-to-Multipoint Transmission (SC-PTM) is a transmission technique currently under development in 3GPP standardization. The main idea in SC-PTM is that in some situations it is beneficial to be able to multicast the data packets in one cell from one base station to multiple receivers that are connected to a cell of the base station. Examples of such a situation include multicasting a specific software update to receivers in the cell, sharing video or data files amongst a group of receivers in the cell, etc.
Some proposals in 3GPP standardization specify that, in SC-PTM scenarios, the UEs receiving and having received the multicast data packets may provide feedback to the base station. One such proposal is 3GPP TSG-RAN WG2 #89bis, R2-151395, titled “Comparison of Unicast and SC-PTM on radio efficiency”. The proposed feedback may involve channel state information that may be used by the base station to adapt the modulation and coding scheme (MCS) of the transmitted multicast data packets. Furthermore, the UE feedback may involve positive acknowledgements (ACKs) and negative acknowledgements (NACKs) relating to the successful respectively unsuccessful receipt of the data packets from the multicast by each of the receivers in the cell.
The positive and negative acknowledgements of each of the receivers consume a significant amount of uplink resources. Hence, there is a need in the art to reduce the number of acknowledgements from the receiver.